1. Field of the Invention
Exemplary embodiments of the present invention relate to a system and method for controlling charging of a hybrid vehicle by operating a hybrid starter generator (HSG) in the hybrid vehicle; and particularly, to a method for controlling the charging of a hybrid vehicle to be charged using an HSG by operating a clutch that adjusts power between an engine and a motor to prevent deterioration of the system efficiency.
2. Description of Related Art
In a hybrid vehicle which travels using the power of an engine and a motor, as shown in FIG. 1, a clutch 13 is disposed between the engine 11 and the motor 12 to allow the engine 11 to selectively assist the power of the motor 12. In other words, when the clutch 13 is joined, the driving power of the engine 11 and the motor 12 is transferred to a driving wheel W through a transmission 14 and a final reduction gear 15 (e.g., an hybrid electric vehicle (HEV) mode); and when the clutch 13 is released, the power of the engine 11 is interrupted, and the driving power of the motor 12 is transferred to a driving wheel W through the transmission 14 and the final reduction gear 15 by the power charged in a battery 19 (e.g., an electric vehicle (EV) mode). In the HEV mode or the EV mode, power stored in the battery 19 is supplied to the motor 12 through an inverter 18.
The engine 11 is connected through a belt 17 or the like to a hybrid starter generator (HSG), configured to start the engine 11 or rotate by the engine 11 and charge the battery 19. In other words, the HSG 16 is configured to charge the battery 19 through the inverter 18 while generating electricity using the driving power of the engine 11 when the clutch 13 is released; and generate electricity to charge the battery 19 while maintaining the driving of the engine 11 when the clutch 13 is joined and the state of charge (SOC) of the battery 19 is substantially low.
Meanwhile, while the clutch 13 is being released for charging by the HSG 16, the efficiency may deteriorate. To release the clutch 13, actual torque output from the engine 11 is required to be adjusted to be zero, and the torque of the engine 11 should be increased to a torque of the charging load of the HSG 16 when the clutch 13 is released. However, in the procedure, the operating point of the engine remains in an inefficient section, thus deteriorating the efficiency. In other words, to prevent physical slip of the clutch 13, the pressure of the clutch 13 is released with fuel injection maintained for the input torque of the engine clutch to be zero, and then the torque of the engine 11 is adjusted to increase to torque capable of dealing coping with the charging torque of the HSG, wherein, in this procedure, as indicated by “A” in FIG. 2, the engine 11 is driven in a low-torque region, causing an inefficient section to occur.